Police in Zambia used tear-gas to disperse angry opposition supporters who protested overnight against presidential election results that showed the ruling party had taken a lead, police said Sunday.

Scores of opposition Patriotic Front (PF) supporters marched in the streets of Mandevu, a populous slum in Lusaka, but were quickly dispersed by the riot police squad, police spokesman Benny Kapeso told AFP.

`We intervened quickly and managed to bring the situation to normal. They started around 9:00 pm at night,` Kapeso said.

The supporters were protesting as PF leader Michael Sata looked set for a narrow loss in Thursday`s presidential elections, which they claim were rigged by the ruling Movement for Multiparty Democracy (MMD).

Mandevu resident Philimon Zulu said the protesters had tried to set fire to market.

`They burnt some stalls in the market before police came in,` Zulu said.

Early Sunday police were deployed in strategic areas of the city while patrols were intensified in slums as acting President Rupiah Banda consolidated a narrow lead over Sata, with results missing from only one of Zambia`s 150 constituencies.

Foreign observers have said the election was clean.